


Ghost of You

by Hirochii



Category: Big Hero 6 (2014), Big Hero 6: The Series (Cartoon)
Genre: BDSM, Control, Domination, Dubious Consent, M/M, Psychopath, identity theft
Language: English
Status: In-Progress
Published: 2018-10-25
Updated: 2018-11-27
Packaged: 2019-08-07 10:15:33
Rating: Explicit
Warnings: Major Character Death, Rape/Non-Con, Underage
Chapters: 2
Words: 9,244
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16406507
Author URL: https://archiveofourown.org/users/Hirochii/pseuds/Hirochii
Summary: Obake. A word often translated as 'ghost', or supernatural beings who have taken on a temporary transformation. It was a fitting name.With only a limited time to live, Obake had plans on taking Hiro as his protégé.  But his plans quickly morphed due to a discovery after impersonating Hiro's deceased brother Tadashi.  The brothers were a lot closer than anyone had ever thought, giving Obake access to unbridled manipulation to the young genius.  Obake, incapable of love and unable to experience guilt or remorse has no inhibitions to act on his immoral sexual impulsive desires without any consideration of the consequences of his actions.  While Hiro, believing that Tadashi had returned as some sort of ghost would stop at nothing to keep his brother with him, no matter how much he had changed.Marked as non/con due to age difference and dubious consent due to impersonation. Recommended that you have completed Season 1 of the Series before reading.





	1. Trick and Treat

**Author's Note:**

> Hey guys! So... I just finished watching all of the Big Hero 6 series and this is what happened.
> 
> The pairing literally nobody asked for.
> 
> Sorry to the people waiting on another chapter from All I See Is You! I've been very busy lately and haven't had the spark to write. This kind of... happened on a whim. Not sure if this will be a one-shot or not. I might continue if you like it or if not just leave it as is.
> 
> Probably an unpopular pairing but heck, I like Obake's cheekbones.

All he wanted was a protege. Without treatment, his time was limited. He was wilting, and fast.

For years he had been obsessed with finding a successor.

Of course, he dabbled with cloning but the process was tedious and the results were unsatisfactory. An exact clone held the same health repercussions that he already had. Of course, he had tried creating an exact clone without the impairment, for what better way was there to test the treatment? But with the same memories and experiences implanted, his clone experienced a paradigm shift and self outrage and disgust. Despite it being amusing to meet a remorseful version of himself, it was unsettling when the clone had decided to self-terminate.

The other option of course was to opt for a younger version of himself. Someone young and impressionable. But there were complications with this and he was forced to abandon hundreds of variants. Those with his memories up until before the accident were too confused and resentful of him. And even with tweaked memories, they was too clever and worked out they were mere copies. The self realisation had interesting but unacceptable results resulting in disobedience and even madness. He had considered biohacking, but he didn’t want a mere subordinate. He wanted an equal.

The closest thing he had come to a successor was Trina, one of his earliest creations and a very impressive piece of tech.

Trina. He made her ten years after the accident. She treated him like he was her father. A curious concept, but he allowed it. It wasn’t uncommon for robots to be self-learning, but Trina even had the ability to self-upgrade her tech and interface. Personally, Obake hadn’t upgraded a piece of her equipment, curious to see just how far she would self-evolve.

She was free to come and go as she pleased, and much like the teenager she was modelled off she wasn’t free of rebellion, sometimes leaving for months on end to start her own fires.

But despite her unlimited capacity to learn, and with the benefit of not having to worry about her mortality she wasn’t a sufficient protege. For while she shared many traits with him, conniving, efficient and manipulative she thought too small. Her creativity was stunted. And to be honest… he just didn’t find her fun. It seemed like a boring option. Where was the challenge?

Another option he had barely considered was having a child. But he had no time to waste on finding a suitable mate, and even if he did what promise was there that the offspring would become an intellectual equal? What use would he have with an infant?

But in Hiro Hamada he may have inadvertently found both.

For the past five years he had been looking into young geniuses and tracking their potential. Most were extremely disappointing, merely slaves to study with no plans for future advancements, wasting their talents on predetermined societal expectations.

A handful showed potential. And with those handful he put them through… some tests. This was the fun part.

What sort of tests?

Well, he had to find out what made them tick. How would they react to a complication? Did they have real world adaptability?

Out of the five candidates, Hiro certainly proved himself sufficient, although it took a while for that ball to start rolling, but once it had… what an interesting turn of events, in his home town no less!

When Obake had manipulated Callaghan originally, he only wanted to destroy Hiro’s technology. Would it break him or what he rebuild making it bigger and stronger? He only wanted to test his mental capability at this stage, not physically damage the boy. Even Obake wasn’t expecting the fire.

And he especially didn’t expect the idiot brother to run inside and get himself killed!

Tadashi Hamada, bless his poor soul.

He had data on that kid too. He was actually one of the earlier candidates when he had first started looking into a successor. Shame he was far too pure! It was sickening, really. And according the reports he ran back inside for Callaghan? What a joke.

But he did have Tadashi to thank for one thing. Through Tadashi, he found Hiro. Fate, perhaps? 

At the age of ten, Hiro was too young at the time. But he drew Obake’s interest. He accelerated at school, but unlike his older brother he refused to participate in extracurricular activities and other things that would look good on a school record. In fact, unlike his older brother, he seemed to do the bare minimum. Hiro preferred to spend his time inventing, pushing his own limit in secret. He would have flown under the radar had Obake not kept tabs on him.

He had a natural draw to the dark, to the dangerous. Bot fighting wasn’t a place for kids, especially for someone like Hiro. But he wasn’t afraid of the illegal. There were definitely some parts in Hiro’s inventions that were far out of the budget of the Hamada family.

But even though he had suspected that Hiro would be a clear frontrunner, Obake had feared he may have prematurely broken him.

Tadashi wasn’t meant to die. It knocked the fight out of Hiro.

But then the fire returned in an unexpected way.

There wasn’t much that Obake didn’t know about San Fransokyo. His former professor, Callaghan, had been easy to manipulate because he knew all about the mishap with Krei Tech. All he had to do was plant some seeds. He didn’t even recognise Obake as a former student.

Callaghan after obtaining the tech of course hatched his own schemes against that rich brat, Krei.

Obake chose to stay back and watch, and he wasn’t disappointed.

Hiro had a natural thirst for revenge. And he was certainly creative, even though a little childish! A superhero team! How thrilling! 

 

But it honestly was a shame about the rest of Hiro’s little squad. All they were doing were holding him back. Hiro would have easily gotten his thirst for revenge filled without them. If he had actually managed to kill Callaghan, it would have made things a lot easier for Obake.

 

But now he needed to test Hiro more. And since he wanted to play superhero, why not indulge him?

And what a surprise! His old dear mentor had returned. Granville. What a perfect opportunity to reconnect!

To his disappointment, there was a huge change in Granville since he had been her student. She had set limits, intentionally holding Hiro back. He noticed that this was incredibly frustrating for Hiro. And of course it was! Growing up a boy genius made it hard for his Aunt and brother to properly discipline him. Children usually have an innate respect for adults, but when a child is at such an intellectual advantage this respect is tarnished.

Meanwhile, San Fransokyo was suddenly infiltrated with a number of villains, some acting on their own accord but ultimately coming together for Obake’s master plan.

And Hiro survived all these challenges. Sometimes in a boringly predictable manner, but at times surprising him, making Obake incredibly proud. It was clearly time to recruit Hiro, but the method… how? This was going to be hard.

Aside from Tadashi, Hiro grew up lonely. Obake noticed that even when he first started keeping tabs on the boy that he had no friends. That barely functional team he had? They were just friends borrowed from his brother.

He had to somehow show Hiro something he desired.

And Trina came to him with the perfect method.

While Trina had disappointed him, she reminded Obake of what Hiro held dearest.

Tadashi had drawn Hiro out of botfighting, why not draw him back into the realm of darkness? He clearly missed the thrill.

With Halloween approaching, he had been given the most splendid idea.

Obake had been quite proud of his theatrics.

The test went well, appearing to Hiro as Tadashi through an illusion through his contacts worked brilliantly.

The plan was simple.

All he needed was Tadashi to convince Hiro that limits will slow him down, that time was precious and he needn’t waste it that he shouldn’t let anyone hold him back. With that deed done, Obake would be able to properly introduce himself to Hiro as a mentor.

Unfortunately the program had a noticeable glitchy effect than a plausible wispy ghost effect to touch. This meant that in order to be convincing, he needed to be present to use the augmented reality software something physical to project onto in case Hiro tried to touch him. Luckily he had enough data on Tadashi to replicate his voice bank to create a vocal modulator in real time. 

Like clockwork, Hiro showed up on time.

“Hey little brother.” Obake had said, turning to face Hiro.

Hiro stood shocked for a moment. Clearly not believing what he saw in front of him had been true up until the moment he spoke. To a logical thinking, science driven mind it was going to take a moment for Hiro to process that he was talking to a ghost.

But what happened next took Obake was shockingly irrational.

He watched as if in slow motion the boy running towards him. 

And then he was drawn down and kissed full on the mouth. 

But he barely had time to register, the kiss quick before he turned to pounding his chest with his fists in a flurry of anger and outrage. His emotions were wild, different than what he had witnessed in Hiro before.

“Why did you run back in there? Why did you leave me? Are you.. Are you real?” Questions were blurted out, almost incomprehensible in the speed they were spoken. 

Obake put his arms around the boy’s shoulders, bringing him into a hug. He was certainly happy that he had chosen to physically appear here, and it was lucky that he had a similar build to the person he was imitating. Hiro immediately relaxed into him, returning the hug.

“There’s something different about you.” Hiro uttered, his voice quiet, but clear in the dead quiet house. He drew himself back and looked up at him, bewilderment and suspicion etched on his face. “And why here, of all places?”

This wouldn’t do, had he seen through the deception already?

“I’m not quite here Hiro. One would usually expect some changes. Anyway, I take you to haunted houses every year, don’t I?”

“Oh!” He seemed convinced. Obake was glad he had bugged the house for that tidbit of information. “So.. are you… Baymax couldn’t detect you… and you keep disappearing… just what are you, exactly? I’ve… I’ve _really_ missed you.” 

Hiro grabbed both of his hands and squeezed them, as if to double check he was real. “Are you… here forever?” His imploring eyes staring deeply into his filled with hope, and something else that made him rethink their interaction.

Obake’s mouth still felt hot from the brief kiss earlier. It wasn’t how one would usually greet a sibling, no matter how long they’ve been apart. The slight intimacies and Hiro’s desperation were also unanticipated. His reaction wasn’t like seeing a return of his brother, it was more like a return of… a lover?

Curious, he tested the waters to see if his hunch was correct. If it was, the hold Tadashi had over Hiro was much stronger than he had calculated and a change in plan may be in order.

He decided to take a risk. The other heroes should have only just been attacked by Noodle Burger Boy, and he hadn’t been alerted of their lenses activating showing their phobias that would give away his ploy to Hiro. He deactivated them with his remote neural transmitter, a perk of cybernetics. This was potentially worth losing that incessantly annoying sidekick.

“I’ll be here as long as I can hold this form. It’s a little strenuous. Come here.”

He wrapped one arm around Hiro’s slender waist and pulled him in, his other hand on his chin, their faces close, but not touching. After a moment Hiro purred, his breath warm against his skin, “What are you waiting for, ‘Dashi?”

That was all the confirmation he needed. Obake smirked, kissing Hiro and claiming him as his own.

 

Being twenty years his senior, despite the severe damage to his temporoparietal junction blurring the lines between right and wrong, even Obake felt a small ounce of trepidation. How thrilling.

The deceit, the game, the sheer surprise of it all.

Oh the surprise! That's just what made Hiro so fun!

And oh dear Hiro, for as clever as he was, he was still only a boy.

Obake didn't doubt his intellectual prowess. Given the right resources and direction Hiro would easily surpass him. But he was far too pure to pursue his rightful destiny. 

Or so he had thought.

It turned out the Hamada brothers had some secrets that even he didn’t know about. Perhaps it was time for him to start bugging private quarters.

After a moment Hiro drew apart and stepped back. His face filled with uncertainty once again.

“What’s wrong?” He asked, trying to add as much warmth and concern into his voice as he could muster.

“Your kiss… it’s different.” The distrust again. Maybe impersonating Tadashi would be harder than he thought.

Admittedly, Obake had been distracted. Perhaps he should have thought more about what was happening in the moment and focus more on the boy. 

“Hiro… the only thing keeping me tethered to this world is you. You have to believe.” Obake said, his voice phasing in and out. To Hiro’s eyes, it looked like Tadashi was fading away like a ghost disappearing.

Threatening Hiro with leaving seemed to do the trick. His eyes wide with alarm, he grabbed at Tadashi in desperation. Obake obliged, letting Hiro see what he wanted to see and phasing back into view.

Hiro sighed with relief and released him. “I’m sorry! It’s just… are you really a ghost? You feel so real, but not what I remember… there’s some small changes… your smell, your taste… I mean… it’s not bad, but just different.”

“Maybe you should sit down?” Obake suggested. Hiro nodded meekly and agreed. Obake took the other seat, relieved by the distance between them.

“Are you really a ghost? How am I able to touch you? Why come back now?” Hiro asked, his voice now steady.

Obake had already made his choice and decided to play the long game using Hiro’s connection to Tadashi as a tool, so he decided to answer calmly. It may be for the best, originally he was just going to rush and tell Hiro to look out for a mentor that could help him on the path to greatness, but in hindsight he was sure Hiro would have seen through the deception.

“I’m dead… I guess I’m a ghost? I’ve been trying to get in contact with you since the fire, Hiro. I’ve been watching you and I’m really proud of you, you’ve done so much! I think you could really change this world. As for why now... I think I’ve only gotten the strength to appear to you now because of Halloween. The spirits are more active.” Obake was having fun. It looked like Hiro was taking the bait, hanging into his every word.

If need be for confirmation, he could appear to the rest of the team, as long as they didn’t notice the contact lenses. That would be his trump card.

“So… you’re probably only here tonight? Unless I somehow get everyone to believe in ghosts? But now that you’re here, I’m sure there’s something I can create to keep you here!”

Obake shook his head, “There’s no need. I think… because we’ve made this connection that it’ll be easier for me to manifest myself to you.”

The both jumped. Hiro’s phone went off, probably one of the Big Hero 6 members requesting backup. Hiro glanced at him, silently asking permission to answer the call. Obake nodded, curious.

“Hey Gogo, what’s up?”

“We captured Noodle Burger Boy!” Honey Lemon’s shrill voice could be heard clearly through the speaker. That was a pity.

“That’s great news! Where are you?” Hiro said, his face lighting up in excitement. Big Hero 6 weren’t the best at securing their enemies, so hearing that one of their adversaries had been caught was great news. “Noodle Burger Boy isn’t acting alone! Have you questioned him?”

This time Gogo answered. Obake had to strain his ears to listen.

“We’re over at SFIT. One problem… once he was captured, his programming reset. He’s back to his normal self and… well, he doesn’t seem to remember anything. So genius, did you want to come over and have a look at his data and see what you can get out of him?”

Hiro lowered the phone and looked over at Obake. “Hey um… there’s a thing…”

Obake smiled, “You should go. I’ll find you again. Don’t worry, I’m always with you.” Before fading from Hiro’s vision.

Hiro stared at where he was sitting for a few moments before picking himself up and heading towards the door.

\---

“That was quick! Where’s Baymax?” Gogo asked him as he burst through the door.

Baymax? Oh, Baymax! That’s right, he had left him at home while repairing him. Did he even close the garage door? Hopefully he was alright!

“Um… I left him at home. I haven’t quite fixed him yet.”

“Oh no! Was the damage that bad? Do you need any help? We can come over after this is all wrapped up.” Honey Lemon piped in.

It was known that Hiro wasn’t only just smart, but he was deadly efficient at solving problems and inventing technology that would usually take years. Repairing Baymax would usually be a piece of cake.

“No it’s fine, I just got a little distracted with Aunt Cass things.” He lied. He had a feeling they would think he had lost the plot if he started talking about Tadashi again. They had already thought he was going a little crazy when he said he was starting to see him around the place, what would they say if he said that he actually talked to him? “Anyway, where’s Noodle Burger Boy.”

“He’s with Fred in there.” Wasabi pointed in the direction of a classroom where Hiro could just make out the tune of the Noodle Burger song.

“Alright, let’s get this over with.” He cracked his knuckles for good measure.

He wanted to get home as soon as possible to get to Baymax… and hopefully Tadashi.

Gosh, Tadashi.

He wasn’t thoroughly convinced that he hadn’t made the whole experience up. He wasn’t a believer in the paranormal whatsoever but… what else could possibly explain what happened?

“Hello, Earth to Hiro?” Hiro blinked rapidly to Gogo’s hand waving in front of his eyes. He was caught staring at the coding on his screen, but his thoughts had wandered back to the haunted house, his finger absentmindedly tracing his lower lip. “You’re all starry-eyed. You’re not daydreaming about Trina again, are you lover boy? Remember she’s a bad guy?”

“Huh? Trina? No… I… sorry, where was I.” He forced himself off auto-pilot, trying to focus on the code in front of him instead of the kiss with Tadashi. It was nice but.. the taste… there was a hint of blueberries. It just seemed a little odd for a ghost.

Disappointingly it looked like any trace of the hacker had been completely erased from Burger Noodle Boy. He kept the the robot shut down, much to Fred’s protest, and to the relief of everyone else. He announced he’d take some parts home for a more thorough investigation, but he was pretty sure that even he would be able to recover anything useful.

 

Wasabi dropped him off and immediately Aunt Cass came bustling out. Hiro sighed, he was going to be in a lot of trouble, already having been caught out for bot fighting just a few days earlier. He was meant to be grounded, although she never had any luck keeping him in.

“Hiro! Where were you? Not answering your phone… and the garage left open, no note, Baymax out in the open with no power! Are you okay? You need to stop doing this! What’s in your bag?” She was caught between being angry and relieved. She half dragged him inside and he willingly obliged. “Sit down!” She told him gesturing to any of the cafe seats while she picked up a donut to help relieve her stress. She looked in his bag but didn’t find his bot, only a CPU and some school books.

She plonked herself opposite him. “Hiro, I really need you to tell me what is going on with you. This isn’t an isolated incident. I thought you were getting better, you know with SFIT and all, but I’m really really worried about you. There’s all this crazy stuff going on in the city now, and I felt safer when you go out at least with Baymax but lately I’m afraid of losing you Hiro, you’re the only family that I have left.”

Family.

 

It wasn’t safe to tell her that he was a part of Big Hero 6, although he really really wanted to. But maybe… he should tell her about Tadashi? Maybe she had seen him too.

“Aunt Cass I’ve… I’ve been seeing Tadashi.”

“Tadashi? What do you mean you’ve seen Tadashi?” Or maybe she hadn’t and she was going to get him committed to a psych ward. Great job Hamada.

“Like… a ghost, or something… I’ve seen him around the past few days and tonight… well, I followed him and I spoke to him. Has he come to you?”

“Hiro… are you feeling okay?” Any hint of anger left her voice, as it always would the few times he mentioned Tadashi. He wasn’t proud to admit it, but using Tadashi was a bit of a get-out-of-jail free card with Aunt Cass. “You’re no”

“Aunt Cass!” He swatted her hand away from his forehead, “I’m being serious! The other night when I went to the haunted house with the gang I saw him… and he’s been everywhere since but no one else can see him but… he’s real… I touched him. Look, he’s right behind you!” He said, standing up so suddenly that the chair fell backwards.

Tadashi waved at him before walking silently up the stairs.

“There’s nothing there, Hiro.” Aunt Cass sounded spooked.

“You… you can’t see him? Oh, great, of course you can’t. I’m… just tired. Maybe… maybe I should go to bed.”

Aunt Cass just nodded, clearly at a loss of what to do.

Once he was on the second level, Hiro bolted up the stairs. Once in his room he closed his door and shoved a chair in front of it. He had his locking rights revoked but it’d still give him some notice if Aunt Cass tried to enter. He left the light off as there was enough light coming in from outside, and he didn’t want to give reason for his aunt to come in.

Tadashi was standing in his side of the room behind the privacy sliders staring out the window. He turned when he heard Hiro approach. Hiro’s heart beat heavily, his emotions a mess between confusion, fright and longing. It was just so weird seeing him back there, like nothing had happened.

“I’m crazy, aren’t I?” Hiro asked, opting to sit in his own bed and merely stare at Tadashi from across the room. It was more likely that he was going mad than to see a ghost, right?

“No, I don’t think so. This is weird for me too. So I’ve noticed… you haven’t really had much time to study, have you? Shouldn’t you worry about the Open House Finals? Your proposal is due in two days and I’m pretty sure you have nothing.”

Hiro groaned, lying into his bed and staring at the ceiling. It really was Tadashi.

“Did you really come back to grill me about academics? I’ll… think of something. I’ve just been busy.”

He felt Tadashi sit at the end of his bed. This was so weird. “I like your Mini-Max by the way. Where’s the big guy anyway? I expected him to be up here.” 

“Baymax? He’s… oh… he’s downstairs… I kind of left him there when you, you know, scared the crap out of me earlier! And what was up with that? Can you at least try and not be so creepy?” He said, punching Tadashi in the arm and was rewarded with a laugh. Hiro couldn’t help but smile back.

What did it matter if other people couldn’t see him?

 

“So I was thinking… for the open day. Why don’t you try making an energy amplifier? I think you might be the only one that could do it, and it would really impress Granville.”

“An energy amplifier? Like… the thing on Granville’s desk? You were there for that?”

“You’ve got no idea.”

“Tadashi! You’re brilliant! Come here!” He positively pounced Tadashi, pulling him back down onto the bed.

It was an awful lot to take in, but he wanted to hold Tadashi as long as he could to make sure he was real. If this was just a dream, it was one he never wanted to wake up from.

Hiro and Tadashi had barely realised their feelings for each other before Tadashi had been so cruelly taken away from him. One of his biggest regrets was not admitting how he felt a lot earlier. So much wasted time!

“God… but an infinite Energy Amplifier in a two week timeframe… and I want it to be powerful! If I had some tech to base it off of it might be doable… but to start from scratch… if I didn’t have my Big Hero 6 duties I might be able to pull it off…” Hiro rambled mostly to himself, just glad that he had Tadashi there to whisper to.

“I’ve researched a little bit into it myself before I settled on Baymax. It wasn’t really my sort of thing but, I can help you with a starting point. You’re on your own from there though!”

Hiro grinned, and pecked his brother on the lips.

The hole in his heart that he had been trying to fix with had been filled again.


	2. Devil In His Heart

**Notes for the Chapter:**

> Things get a little spicy.
> 
> It's a little odd coming from writing a long time Hiro/Tadashi fic to writing a character like Obake!

_“Absolutely not Mr Hamada!”_

Professor Granville had vehemently rejected Hiro’s proposal leaving Hiro in a sour mood. He hadn’t thought of a backup, and if it wasn’t for Tadashi’s idea he wouldn’t have thought about the science fair whatsoever.

He had been easily coasting at SFIT. Despite being 14 years old, the classes were exceedingly easy and even with Big Hero 6 taking up the majority of his spare time due to the villain problem in San Fransokyo he hadn’t found the school to be a challenge whatsoever. It seemed the only exception to that rule was Professor Granville who was twice as hard on him as the other students.

And the annoying thing was, it wasn’t that her lessons were particularly hard. When push came to shove, usually 2am in the morning before something was due, he always produced exemplary work that would ordinarily blow a teacher away. But not Granville.

She was just so incredibly vexing. She caught every second of late attendance or when his attention was slipping class.

  

It didn’t help that the rest of the team didn’t seem particularly impressed by Hiro’s proposal idea either. They reminded him of how dangerous supercharging was and there was barely any time to prepare something so complicated. Wasabi especially was adamant that he should change his proposal. But Hiro could see the gap in the market. Despite the phenomenal technological advancements in recent years, there was still a huge room for improvement in power which was largely overlooked in favour of flashier innovations.

“I heard that you don’t have anything for the Science Fair.” An annoying voice broke through his reverie as he stared into the sloppy cafeteria food.

“Not now _Karmi_.” He said dismissively, barely looking up at her.

“I’m just saying, you better get a move on. You might have to repeat the year if you don’t… but I suppose that’s not entirely unsuspected. I’ve already finished mine of course. Did you want to see it?”

Hiro’s groan of ‘not really’ wasn’t heard over the rest of the team’s enthusiasm as they clambered to take turns looking through the microscope that Karmi inconveniently planted right in front of him. Karmi’s biology projects were never really that interesting to him… but, he had to give her some credit for this one. It was right up his alley afterall.

She had worked on a new way of controlling nanobots using natural animal swarm behaviour essentially creating bio-inspired nano-robotic swarm. He had wondered why she was poking around asking him about nanobots a few weeks ago, and it looks like she had put his advice to good use. It was only in its rudimentary phases and Hiro could see ways to improve it but the implications were there: it meant that nanotechnology could execute complex tasks inside a living animal.

It irked him that while Karmi had finished her project while he was only met with opposition from Granville. _’Too advance of an undertaking, even for your Mr Hamada’ _were her words. She even had the absolute nerve to call him arrogant... well, maybe she was right but he sure as hell wasn’t going to let this go. He would just have to prove her wrong!__

__“You don’t want to see?” Karmi asked him when he stood up abruptly to leave. She seemed hurt making him feel a little bad. He mumbled something about having to finish his own project and waved absentmindedly to the gang._ _

__Technically he’d be skipping the afternoon period, but he wasn’t particularly worried because Granville didn’t teach that class and none of the teachers seemed to have a problem with him. Besides, he still had some tinkering to do on Baymax. While he should be fully restored, he hadn’t had time to initiate diagnostics before he had to leave for school in the morning and had decided to leave him charging and dormant._ _

__Ducking under the window and bypassing the cafe so Aunt Cass wouldn’t notice him home, Hiro headed straight for the garage._ _

__“Ouch.” Hiro said unconvincingly._ _

__As expected the health-care robot awakened, scanning him and concluding that while he was healthy, he was sleep deprived and needed to drink more water. The lollipop was an added bonus._ _

__Hiro smiled, plonking himself down in the work chair and kicking his feet up on the desk, allowing himself to sigh heavily. Everything appeared to be in order._ _

__Except for Tadashi._ _

__He hadn’t seen him since he had fallen asleep, and he tried his best to get it him of his mind. He was more than convinced that it was some sort of ethereal dream because there was no absolutely no logical way for Tadashi to be back._ _

__

__“Tadashi? Are you here?” Hiro said quietly, but hopefully, for the second time that day._ _

__“Hiro, would you like to see videos of Tadashi?” Baymax’s soothing voice asked from behind him. Tadashi wasn’t here._ _

__“I… uh… not now, Baymax.” He hadn’t been able to bring himself to look back through Baymax’s recordings since the first time the robot had showed him. It hurt too much._ _

__

__As for Tadashi… Everything had felt so real. He was quite possibly going crazy. Maybe he should update Baymax’s mental health database? No… The thought of talking to Baymax about his feelings was somehow comical, even if he was a healthcare professional._ _

__But what he did know was real was the proposal idea Tadashi had left him. The energy amplifier to minimize energy loss. But without the guidance of his ghostly brother, even Hiro didn’t have enough of a starting point to actually pull off the feat in the given amount of time. Most of the students had been working on their projects since the beginning of the semester. If he weren’t starting from scratch it wouldn’t have been a problem._ _

__The thing is, he just didn’t have _any_ tech to base it off. As far as he knew, this was new territory. He knew a general endpoint. Only a few months ago when he had finally brought Baymax back, Yama had tried to steal a powerful magnetic energy ‘paperweight’ that amplified energy and had almost sent Baymax into orbit. But overall he was aiming for something with a bit more control than that.. But no less powerful._ _

__Hiro groaned again, leaning forward and burying his head on his hands heavily enough to stir the mouse and wake his monitor up._ _

__“Huh?” He uttered to himself, a news article that he didn’t recall reading was on the screen dating twelve years ago._ _

__“Failed Krei Tech Prototype May Cloud Future of Energy Evolution.” Baymax said helpfully behind him, reading out the article headline._ _

___’I’ve researched a little bit into it myself before I settled on Baymax. It wasn’t really my sort of thing but, I can help you with a starting point. You’re on your own from there though!’_. Is this what Tadashi had meant by a starting point?_ _

__

__An hour of research later taught him nothing other than the failed project was still located at Krei Tech and that the technology was considered highly unstable and unattainable. That just made him want to make it even more. Besides, Krei was renown for launching products too soon, he highly doubted success was impossible._ _

__Maybe it would be worth a visit to Krei? The entrepreneur certainly owed Big Hero 6 more than a few dozen favors… that being said, Krei did know their secret identities and hadn’t been particularly grateful to them in the past._ _

__So… that left him with three options. Start from scratch and most likely fail the semester, come up with a new proposal altogether, or break into Krei Tech and _borrow_ the amplifier._ _

__Option one… sure he had _some_ idea of what to do, but he couldn’t think of coding it feasibly in less than a year, let alone a few days._ _

__Option two… made the most sense. And it’d be what his brother and everyone else would want him to do, right?_ _

__Option three… But maybe it wouldn’t be so bad if he just borrowed it for a little bit. Besides, when he was done he was sure that Alistair Krei would be more than happy to purchase the device off of him so he was really doing him a favor._ _

__It’s not like he wanted the energy amplifier for any particular reason other than to prove that he could make it. And maybe Tadashi would want him to complete the proposal… why else would he suggest it?_ _

__Hiro shook his head, trying to get the ghost of Tadashi out of it. But this article was proof, wasn’t it? He wasn’t just making this up and sleepwalking in San Fransokyo. Some sort of energy was keeping Tadashi tied to the earth… what if this was the path to grounding him here permanently?_ _

__Ugh. What a wild idea. _One step at a time, Hiro!__ _

__\---_ _

__It looked like everything was going according to his new plan._ _

__

__Obake observed his young protege through his surveillance cameras which he had set up in Hiro’s bedroom and garage when the boy had fallen asleep._ _

__He had also managed to make a few other small changes while he was there._ _

__He also activated his lenses on the other heroes, although one of them, the idiotic mascot had been asleep. The rest had been busy studying and working on their proposals. He gave them a quick vision of Tadashi. No words, only an appearance next to them or in Honey Lemon’s case a reflection in her mirror. Just enough to spook them so if Hiro started babbling about seeing a ghost at school he would feel a little less crazy. He didn’t want his protege falling into psychosis._ _

__The contact lenses he had fitted the heroes with were naturally dissolvable, so if they hadn’t noticed them already they would have already disintegrated which meant he needed another way to get to Hiro._ _

__Baymax had been carelessly left in debug mode from Hiro’s abrupt departure making it easy for Obake to make some undetectable minor alterations to his programming._ _

__Obake had also left behind some upgraded ‘Buddy Guards’. The drones which were originally created by Krei Industries had proved to be extremely useful due to their ability to fly, but most importantly because of their invisibility using Flexible Display Technology and their ability to camouflage… or in this case, appear as Tadashi Hamada at will they were the perfect devices for his plans._ _

__Hiro had taken the bait, hook, line and sinker and seemed more determined than ever to crack the code behind the energy amplifier. Obake believed he was more than up to the task. His mind was exemplary but there was no way the boy could start from scratch in the timeframe given._ _

__And if he knew Hiro, the boy would be far too stubborn to alter course, especially since it was suggested to him from such a divine intervention._ _

__On most counts, not much had deviated from Obake’s original plan._ _

__To begin with he was going to task Globby with stealing the flawed energy amplifier from Krei, as he was sure that it would spark the idea for Hiro to recreate the technology perfectly. He knew that Hiro needed inspiration, the boy was too busy playing superhero to take his academics seriously._ _

__But now there was no need for such a complicated plot to steal the amplifier. Not when Hiro would so willingly give it to his long lost brother. Or should he say lover? Such an interesting little rulebreaker Hiro was._ _

__

__Hiro had dismissed Baymax and started work in silence. It looked like he was going to at least attempt to create the energy amplifier from scratch. Obake left the surveillance cameras to work on his own nefarious projects. It was near completion, and once Hiro brought him the final piece of the puzzle it would be complete._ _

__Of course, it wasn’t just about the destruction of San Fransokyo. If he wanted to do that it would be more than easy to simply deploy a bomb. He just wanted to do it because he could, and he knew Hiro wouldn’t be truly his if he had San Fransokyo to turn back to. No, it was better to erase that part of him._ _

__He wasn’t sure how many hours had passed until something on the surveillance cameras caught his eye. Hiro had turned the lights off to the garage and made his way upstairs. The teen wore his emotions on his skin, and the irritation from his project was clear on his expression and the way he was walking._ _

__Reaching his room, he walked right past his own bed and stood in front of Tadashi’s section of the room. Obake contemplated sending the Buddy Guard to him but decided to watch for a little longer instead._ _

__“Tadashi, are you here?” Hiro asked quietly and hopefully._ _

__If Obake had the capacity to feel empathy he would have felt a little sorry for him. But luckily, he didn’t._ _

__The boy approached the bed, got down on his knees and reached deep under, giving the man a great view of Hiro’s perky behind. After a moment the boy drew out a small white box. He sat down on the bed with a huff and dusted off the top. After opening the lid he stared at the contents intently. Frustratingly, Obake wasn’t able to get a good look inside and he was curious about what had been hidden away._ _

__He wasn’t kept guessing for long._ _

__Putting the box to the side, the teen kicked off his sneakers, quickly followed by shimmying off his baggy cargo pants and underwear in one go. He shrugged off his jacket, but in his adolescent excitement didn’t even bother removing his shirt._ _

__He had completely changed from the frustrated Hiro he had been watching earlier. His cheeks were flushed and there was a light sheen on his skin, perspiring from excitement. He was fully-erect and his modest penis was hard, lewdly peeking out from his oversized shirt. Visibly shaking from either nerves or anticipation he reached into the box, drawing out a relatively small but realistic dildo and and a bottle of lube._ _

__

__Hiro generously squirted lubrication onto a couple of his fingers. Hiro’s breaths were hot and heavy as he leant back and tried to relax as he touched himself on his special spot. His eyes squeezed shut and an expression that read more pain the pleasure was evident on his features when his first digit entered. With his spare hand he took a hold of his cock, and the pain escaped his features to be replaced with an audible moan._ _

__Obake smirked, pleased by the further confirmation of Hiro’s perverse persuasions. Obake didn’t have the capacity to love, and without conscience he was uninhibited in his expression of sexual desires. He now didn’t just see Hiro as a potential protege, but also an object of pleasure and satisfaction._ _

__

__He employed many tools and techniques to influence and control the minds of others. It’s how he brought together his villainous friends by playing on their insecurities. While he watched Hiro pleasure himself, he could tell that the boy was out of practice. His awkward movements along with the box seemingly being untouched for at least a year made him believe it had been a while since he had instigated anal play. Apparently seeing his brother again was enough for him to bring back fond memories._ _

__He pondered how he could form an intimate relationship with Hiro. His desire for complete power and control overtaking his obsession to find a free-thinking heir. The easiest route was using Tadashi’s image, but while it would work to begin with it would serve irritable and hard to maintain. No, he needed to somehow convert his affections and thus gain his unbridled loyalty, and sexual control was one of the easiest ways, especially in someone still developing their inclinations._ _

__Hiro’s panting became heavier as he finally managed to gain some traction working the toy inside of him. The near inaudible word on his hot breath sounding like ‘Dashi’. Abandoning his erection, Hiro had rolled onto his knees, face down in his pillow and ass pointed lewdly in the air as he tried to work the dildo in a further inch. The toy was only small in size, the insertable length couldn’t have been any longer than 5 inches long and was narrow in circumference, but he was still struggling to penetrate deeper._ _

__Intrigued to find out his reaction, keeping the Buddy Guard in invisible he had the robot come closer to the bed. Activating the voice system, he spoke clearly into the microphone, his voice programmed in real time to convert to that of Tadashi Hamada._ _

__“Just relax Hiro, if you’re tense it’ll only make it harder.” He said calmly. To his amusement, Hiro yelped in surprise, sitting up abruptly to look around. The toy slipped out of his tight entrance with an audible plop._ _

__Blushing a deep crimson the boy had gathered the blankets to cover his lower half. He looked around for the disembodied voice to no avail. “Tadashi? Are you here?” He asked out loud to the dark room. Obake decided it was safer to keep the apparitions at minimum given Hiro’s penchant to physical contact._ _

__“I’m always here. I just don’t always have enough energy to contact you.” Obake knew what he was saying was bullshit, but he knew well enough that even though Hiro was a genius, he was filled with human emotions and irrationality and would willingly pull wool over his own eyes if it meant spending more time with his loved one._ _

__“Energy? Energy! There must be a way to keep you here… just like how you were last night. I could… I could _feel_ you!” Hiro began asking questions to thin air about the afterlife and whether the energy amplifier would be able to bring him back. Obake hadn’t considered that leap and pondered briefly on it. If Hiro thought it would help it would definitely make him do absolutely _anything_ to achieve his goal._ _

__“I’m going to be honest with you Hiro… Things work differently here. I don’t know how but I think if you successfully build it, you’ll be able to keep me grounded.” To Obake’s disappointment, the earlier mood had dissipated due to his interruption. That wouldn’t do at all. “Anyway, why did you stop? I was enjoying watching the show. I want to see how much you’ve grown.” He added slyly._ _

__\---_ _

__1½ Years Ago_ _

__Ugh, what was Tadashi doing home already? As he stepped into the attic he wasn’t expecting to be confronted by his brother._ _

__“Knucklehead, did you use my card to order parts again? You know all you had to do was ask, right?” Tadashi said, noticing Hiro trying to hide a parcel behind his slim waist. “You’re not ordering more things for your bot, are you? I thought you quit that.”_ _

__Hiro tried to escape, but was too slow for his brother’s longer limbs which drew him into a tight hug. This wasn’t fair! Tadashi knew his weakness! He easily pried the package from behind him and gave Hiro a quick peck on the forehead before releasing him._ _

__He watched Tadashi grab the nearest pair of scissors and easily slice through the stickers sealing the box. Hiro felt like a deer in headlights stuck between fight or flight. It was really tempting for him to run away, knowing what his brother’s reaction would be based on their previous conversations on the topic but something kept him stuck there to watch the car crash._ _

__“Oh.” Tadashi said simply staring into the contents of the package, crimson appearing on his face all the way to his ears._ _

__Hiro’s expression mirrored, blushing furiously he uttered, “I was going to tell you… well, you wouldn’t listen… I just wanted to try it.” His excuses were mumbled and sounded feeble to his own ears. He remembered the conversations with his big brother vividly._ _

__Hiro and Tadashi had been playing cat and mouse since Hiro’s high school graduation. It had quickly become clear that they both had romantic feelings for each other, but Tadashi’s pride of playing the role of a good big brother had caused him to distance himself from Hiro and focus on his project Baymax. Hiro in turn had felt somewhat abandoned by Tadashi, and rebelled by entering the realm of bot fighting._ _

__Only recently had they begun to patch things up and be honest with their feelings. Tadashi had argued that while there was a degree of physical attraction between them, they had to work past the feelings and remain platonic. Hiro had boldly countered with his best constructed argument. A full kiss on the lips that was momentarily returned with the same amount of passion._ _

__Thus, a compromise was made much to Hiro’s chagrin. They agreed they wouldn’t have sex until Hiro was at least 16. It would have been 18 if Hiro hadn’t put his foot down._ _

__And yet, only two weeks after that conversation Hiro had already been caught out with a sex toy! In Hiro’s defense, he did order it prior to the agreement. And besides, Tadashi hadn’t explicitly ruled out using toys._ _

__Tadashi coughed, “It’s okay Hiro, I understand.” He closed the lid, giving the box back to Hiro. ”Just be safe when you’re using it.” Tadashi then excused himself from the room, but Hiro was perceptive enough to notice the hardening in his pants that he tried to hide. Hiro grinned after Tadashi. Maybe with enough exposure he’d be able to weaken his brother’s defenses?_ _

__And perhaps with a bit more time he may have, but then he died._ _

__\---_ _

__

__“Remove your shirt.” Tadashi’s disembodied voice instructed him._ _

__

__And just like that, Hiro was brought back to the present. He responded a little too energetically, removing his shirt so quickly that it earned him a chuckle. Filling silly, he also removed his socks making him completely nude._ _

__In death, Tadashi seemed so different._ _

__But maybe that was to be expected. In the living world he had to worry about what was right and wrong, but now… it was just them. The earthly societal constructs that bound him were now irrelevant. Maybe this was what Tadashi would have been like without his inhibitions._ _

__“You’re thin. You’ve been too busy with Big Hero 6 that you’ve been skipping meals. You should take better care of yourself.” It was a statement that he couldn’t argue with. The villain problem in San Fransokyo was reaching unprecedented levels ever since Big Hero 6 had formed, and even worse still it seemed that they had been gathering under a single leader. Obake._ _

__Obake was a mystery to him. He couldn’t understand his motives at all. It was like he was wreaking havoc just for the sake of it. He was sure there was some big end goal but he couldn’t foresee what it was. At least all the other villains had some sense behind them._ _

__“Sit back in bed Hiro, hold your legs up. Show me everything.” Tadashi’s voice brought him back to reality. “Why so shy Hiro? You’re usually so brash.”_ _

__Red with embarrassment, he did as instructed. He rocked back, legs up in the air and hooked his hands behind his knees, clearly exposing his privates. He was almost glad he couldn’t see Tadashi because he felt like he was going to die from humiliation. With no one to fix his eyes on, he kept his eyes closed, focusing on his brother’s voice._ _

__“Very good, Hiro.” Tadashi purred, his voice close to his ear. His heart pounded loudly in his chest in exhilaration. In spite of his humiliating position, Hiro was rock hard again. He had never been so entirely exposed before._ _

__He was instructed to finger himself and was hushed when he tried to feebly protest. Resigned, he pressed a finger against his entrance which slipped in rather easily from the lube residue. It felt good. It felt _really_ good and he didn’t need further instruction to continue pistoning in and out as he imagined Tadashi standing over him beating his cock while watching him masturbate._ _

__Hiro had abstained from anal play since his brother’s passing. Even though they were never intimate, it reminded him of Tadashi because he always imagined it was his brother teasing and even penetrating him. He had only used the toy a handful of times and Tadashi had ever only walked in on him once and his reaction had been very different. But now the mixture of pleasure and humiliation he felt masturbating in front of Tadashi was overwhelming and he almost came without even touching his own pounding cock._ _

__“Don’t come yet, Hiro.” Tadashi whispered, bringing him back from the edge, “I want to see you use the toy again. Properly this time.”_ _

__“O-okay.” Hiro agreed nervously, withdrawing his hand and sitting up to re-lubricate the phallus. With his eyes open he was surprised to see Tadashi standing at the end of the bed. He wasn’t naked like Hiro had envisioned, but still in the same outfit. The outfit he had died in._ _

__“Stay in bed. I can’t hold a corporeal form right now so we can’t touch each other.” Ghost Tadashi seemed cold and distant, and the gaze he held reminded him of the first few sightings he had of his brother. The uncanny visceral feeling in his body reminding him that he was dealing with something supernatural and outside his scope of understanding. “Go on, what are you waiting for?”_ _

__Averting from his cold eyes, Hiro focused on his brother’s soft lips as they issued him further instructions. He thought he’d be asked to insert the toy straight away, but he complied when instead he was instructed to run his hands over his body. At some point he closed his eyes again, imagining the touch was from Tadashi._ _

__He gasped sharply when his fingers brushed over his nipples. Hiro had never taken the time to properly explore his body. In the past year, masturbation had turned into a quick duty to clear his mind with pleasure almost an afterthought. Tadashi noticed his nipple sensitivity and told him to focus on them. His penis throbbed and his hips involuntarily bucked at the touch._ _

__He reached down with his left hand to grab a hold of his cock but he was instructed not to touch it. Hiro pined, emitting a shameful noise at having to resist touching his erection. Tadashi suggested to use the dildo again, and keeping his eyes locked on his brother he pressed the tip against his entrance. His body, hot from the foreplay, and with the encouragement of Tadashi accepted the toy with relative ease and he managed to handle 4 of the 5 inches of the insertable length. He breathed heavily, adjusting to the feeling of being filled._ _

__“Good job.” Despite the intense delivery, Hiro’s heart leapt at being praised by his brother again. He missed that feeling _so_ much. “Now relax, breathe, and work it all the way inside of yourself.” Determined to put on a good show, Hiro vowed to do his best._ _

__He forced the rest of the toy inside of him and Hiro moaned so loudly that he was suddenly very glad that he had left Baymax downstairs as he was sure that would have activated him. Panting heavily, he gave himself only a moment to adjust before working it in and out of his body. Tadashi was smiling now but aside from that he had no other reaction._ _

__It felt so demeaning being so naked and exposed, masturbating in front of his fully clothed brother and yet it somehow turned him on even further. Hiro began to lose himself to pleasure, and closed his eyes again as felt himself come closer to orgasm._ _

__He moaned loudly as he released himself without even touching his erection. Cum pooled on his soft stomach and chest as he finally released the dildo, too tired to even remove it. Through his fluttering half closed eyelids he could see his brother disappear._ _

__“Tadashi, wait!” He exclaimed sitting up with renewed vigour, not caring about the mess._ _

__“You did well Hiro! But it’s hard for me to hold a form.”_ _

__He had forgotten. He needed to create the energy amplifier and didn’t have time to muddle around figuring out the basic code. Hiro quickly cleaned himself up, glad that there were still tissues on Tadashi’s bedside table and got back into his clothes._ _

__“Where are you going?” The disembodied voice asked him, noticing that he was on a mission._ _

__“Krei Tech. I need to… borrow something.”_ _

__“Borrow something? It’s 2am in the morning. You’re stealing the failed prototype, right?” Of course Tadashi wouldn’t condone such an act, but Tadashi wasn’t in a position to stop him._ _

__“No… uhh, it’s something else. Official Big Hero 6 business. I’ll be back soon.”_ _

**Notes for the Chapter:**

> Please leave a comment if you enjoyed this so I know I'm not the only person in the world that ships this!

**Author's Note:**

> Please let me know what you think! Leave a comment - I'm curious!


End file.
